Conventional DVD recording and reproducing apparatuses support video signals only of standard-definition television (SDTV) systems. Such recording and reproducing apparatuses record thumbnail images or content information on discs. When playing the discs, different recording and reproducing apparatuses (or the same recording and reproducing apparatuses as well) can show users the content information on the discs by generating on-screen reproduction menus from the recorded information and displaying them, or by displaying disc menus, configurations of which have been recorded on the discs so that the disc menus can represent on-screen menus as are intended by those who have recorded them.
FIG. 1 shows an example of an on-screen disc menu 700 displayed by a conventional recording apparatus. The conventional on-screen disc menu 700 displays content recorded on a recording medium as a list of thumbnail images so as to allow a user to select a content item with ease. As FIG. 1 shows, the disc menu recorded on the recording medium has a size (particularly, with regard to the number of thumbnail images) appropriate for an SDTV resolution as a standard resolution.
To perform a format operation to erase entire content recorded on a disc using any of such conventional recording and reproducing apparatuses, first the user has an on-screen menu displayed, browses thumbnail images, and judges whether or not each and every content item is necessary. Then the user performs the format operation.    Patent Reference 1: Japanese Unexamined Patent Application Publication No. 2004-5776